How long after Benadryl do hives go away
How long can hives last?
Hives can appear and disappear quickly, with each hive only lasting around 23 hours. However, depending on the cause, they may reappear and continue affecting someone for days, weeks, or longer.
People can have acute hives, which occurs due to a specific trigger and resolves within
This article looks at how long hives last, factors that influence their duration, and treatment.
Each hive lasts only
Acute hives appear quickly and do not last long. Doctors classify hives as acute if the overall duration is less than 6 weeks.
However, around 25% of people go on to develop chronic hives. This is when hives regularly reappear over 6 weeks or more.
For many individuals, chronic hives eventually clear on their own, but this can take months. According to the American Academy of Dermatology Association (AAD), around half of people with chronic hives spontaneously recover within 1 year.
Acute hives often occur in response to an allergen or irritant. When the immune system perceives a substance as a threat, it releases histamine and other chemicals. This causes tiny blood vessels under someones skin to leak fluid, which accumulates and causes the bump.
Some
- food allergens, such as milk, eggs, tree nuts, peanuts, or shellfish
- contact allergens, such as latex or animal dander
- insect bites or stings
- medications
Any drug can cause hives, but some of the medications most commonly associated with this symptom include:
Acute hives can also occur in response to viral infections, parasitic infections, or during times of stress.
According to a 2018 review, doctors are unsure of the cause of acute hives in
Chronic hives may have the same cause as acute hives, but with symptoms lasting longer than 6 weeks. However, chronic hives are often not due to an allergen and instead have a physical cause.
There are two subcategories of chronic hives: inducible urticaria and chronic idiopathic urticaria.
Chronic idiopathic hives
Chronic idiopathic urticaria has no clear cause and is the most common form of chronic hives. Researchers are working to understand why this type of hives occurs, but a leading theory links it with autoimmunity.
Autoimmunity occurs when a persons immune system mistakenly attacks healthy tissue, and several autoimmune conditions are associated with chronic hives. The most common is thyroid disease, which is present in
This suggests that the hives may result from someones immune system not functioning as it should. Other conditions that can occur alongside chronic hives include type 1 diabetes, lupus, and rheumatoid arthritis.
Infections can also be associated with the onset of chronic hives. This includes bacterial, viral, and parasitic infections. Again, this may result from autoimmunity an infection may trigger a change in how the persons immune system works.
Inducible hives
Inducible or physical urticaria is less common than chronic idiopathic urticaria. With this subtype, it is possible to purposely induce the hives by a person exposing their skin to certain triggers, which could include:
- Scratching or pressure: The
most common type of inducible hives is known as dermatographia. This condition involves developing hives as a response to scratching or drawing on the skin. - Cold: Cold hives occur on someones skin or mouth after exposure to cold temperatures. Triggers include consuming iced drinks, touching cold water, or going outside in cold weather.
- Heat: Cholinergic hives occurs when an individuals body becomes hot or sweaty. Hot baths, exercise, and spicy food can be triggers.
- UV light: Solar hives occur in response to UV light from the sun and certain light bulbs, such as those in tanning beds.
- Water: Some people develop hives if their skin comes into contact with water. This is known as aquagenic urticaria and is very rare.
Doctors diagnose hives by performing a physical examination. There is no test to determine whether the persons hives are acute or chronic, so they will use the length of time they recur to do this.
The doctor may also ask an individual:
- when the rash began
- the shape, size, and distribution of the rash
- where on the body they first noticed the rash
- if they have had any insect bites
- if they live or work with common hive triggers, such as chemicals, animals, or latex gloves
- if they have bone or joint pain, fever, or abdominal pain
- if anyone in their family experiences hives
- if they take any medications or supplements
The doctor may use a skin prick test and serum-specific IgE test to check if the acute hives result from a specific substance, such as food, dust mites, or chemicals. Alternatively, they may refer someone to an allergy clinic for these tests.
However, in cases of chronic hives, allergy testing is rarely useful. A doctor may check for other underlying health conditions by performing additional tests, such as:
The most suitable treatment depends on whether the person has acute hives or chronic hives.
Acute hives
Doctors typically recommend second-generation antihistamines as the first-line treatment for acute hives, such as:
- loratadine (Claritin)
- desloratadine (Clarinex)
- fexofenadine (Allegra)
- cetirizine (Zyrtec)
- levocetirizine (Xyzal)
They may prescribe a standard dose or increase by up to 4 times if the individual does not respond.
If these medications do not improve symptoms, the doctor may recommend an additional antihistamine, such as cimetidine (Tagamet), famotidine (Pepcid), or ranitidine (Zantac). They may recommend a 310-day course of corticosteroids to help control the symptoms in severe cases.
The doctor may prescribe an epinephrine auto-injector if they think the individual is at risk of anaphylaxis, which is a severe allergic reaction that restricts breathing. This provides emergency medicine to treat anaphylaxis quickly.
The doctor will then reassess the individual in 26 weeks.
Chronic hives
Doctors may recommend a four-step treatment plan for chronic hives. This approach involves using an antihistamine daily, which may be up to 4 times the regular dosage depending on how the individual responds.If necessary, they may prescribe a second antihistamine or another medication, such as montelukast (Singulair). With persistent hives, they may suggest a high potency antihistamine, such as hydroxyzine or doxepin.
The final step is for a doctor to refer the individual to a specialist for immunomodulatory therapy. This may involve taking medications such as omalizumab (Xolair) or cyclosporine (Sandimmune).
Once symptoms are under control, a doctor may gradually reduce the dosage of these medications. If the hives have an identifiable cause, such as cold or heat exposure, adopting changes to avoid the triggers wherever possible is also important.
The AAD suggests the following methods for people to reduce irritation and itchiness in hives:
- applying topical anti-itch medications, such as calamine lotion
- wearing loose-fitting clothing
- moisturizing with fragrance-free lotion to prevent dry skin
- using cold compresses several times per day
However, it is important for individuals to try to determine whether the hives have a specific trigger, in addition to relieving symptoms. If someone has cold hives, for example, a cold compress may make them worse.
Therefore, it is a good idea for people to keep a symptom diary, recording when the hives occur and any factors that might have contributed. Symptom diaries are also useful to refer to at medical appointments. A person can take note of:
- the date and time the hives appear
- what they were doing just before they developed
- what they have had to eat or drink
If any common factors emerge when the hives occur, a person can try to temporarily avoid these to see if it helps. It is important for people to do this with the guidance of a doctor, allergist, or dietitian if someone has food-related hives.
Learn more about remedies and treatments for hives here.
Hives do not last long, taking only 23 hours to fade. However, more can appear, which makes the symptoms last longer. Acute hives can develop and resolve on their own within 6 weeks, while chronic hives can last much longer.
Doctors treat acute and chronic hives differently, so it is advisable for people to speak with a medical professional about this symptom, especially if the hives last longer than 6 weeks.
If hives or swelling occur in the mouth and airways, making it difficult to breathe, dial 911 or the number of the nearest emergency department immediately.
Hives (Urticaria)
What are hives?
Hives, or urticaria, are flat red welts that can appear anywhere on the skin and usually itch. Hives often occur as an allergic reaction to something eaten or something that has contacted the skin. Foods, medicines, and plants are common causes, but sun exposure, stress, infections, and autoimmune diseases have also been known to cause hives.
Symptoms include an itchy, stinging pink rash of slightly swollen skin. The rash may wax and wane in severity. Acute hives typically resolve within six weeks, but chronic hives (urticaria) can persist for months or years.
Hives often resolve on their own, especially in children. Otherwise, treatment for acute hives involves oral antihistamine medications to help relieve the itching and stinging. Chronic hives that do not improve with antihistamines may be treated additionally with corticosteroids, antibiotics, and other stronger medicines. A study found that 35% of people with chronic hives, are symptom free within one year, with another 29% having some reduction of symptoms.
You can safely treat this condition on your own as long as you does not develop trouble breathing. Any antihistamine (like Zyrtec, Clarinex, etc) works.
Why won't my hives go away?
Q.I've gotten hives from time to time when I've been overly stressed. But now I have a case that won't quit after six weeks. What's going on?
A. No one welcomes these red, itchy welts that crop up on our skin. Many things can lead to a temporary case of hives, including allergic reactions to food, medications, bug bites, pollen, latex, or animal dander. Like you, some people also develop them when they're stressed, or in response to ultraviolet light or excess skin pressure. Hives are more common in women than men, especially from our 30s to 50s.
Most cases of hives go away within several days to a couple of weeks. If they last six weeks or longer, you may have autoimmune hives. This happens when your immune system mistakenly targets healthy tissue in this case, triggering a skin reaction. Autoimmune hives are more common in people with other autoimmune conditions, such as lupus, thyroid disease, rheumatoid arthritis, or celiac disease. Anyone whose hives last longer than a few weeks should see a doctor.
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When is a drug rash more than just a rash?
You were recently started on antibiotics for an infection and you are now doing well. But slowly your skin begins to itch, and the telltale signs of a rash are already popping up first on your torso, and now spreading to your arms and legs. What do you do? Should you worry? Should you see a medical professional?
Rashes are a common and pesky side effect of many medications. It can be so disheartening to be getting better from one ailment only to discover that you have another issue to address. While these itchy eruptions can be annoying, they usually run their course over a week or two and can be treated with topical medications.
But not all drug rashes are created equal and some can even be deadly. Luckily the scary ones are pretty rare, but it's still a good idea to know how to spot them. How can you tell the serious rashes from ones that are just a nuisance, but will get better with time and treatment?
Types of drug rashes
There are two main allergic rashes that may happen after taking a drug. The most immediate type of reaction happens within hours. Hives appear and move around the skin. Since this process is related to the release of histamine, antihistamines (available over the counter at a drugstore) are the typical treatment.
There is also a delayed type of drug rash that comes up four to 14 days after you start taking a medication. Pink and red bumps appear on your chest and back, and spread to the arms and legs over the course of days. Unlike hives, these bumps don't move around, and after a few days things may start to get better, but you may have peeling skin much like a healing sunburn.
This delayed type of rash doesn't respond as well to antihistamines, but an over-the-counter topical cortisone cream (or one of its stronger prescription-strength versions) can help speed the healing process along.
When is a drug rash cause for concern and a visit to the ER?
With hives, the main concern is that you're experiencing a whole-body reaction that goes beyond the skin, one that can make breathing difficult or dangerously drops your blood pressure. If you experience either of these symptoms, it's very important to get to the ED.
These immediate, life-threatening reactions can be treated with steroids, epinephrine, and higher-dose antihistamines than you can find at the drug store. While they are scary, these types of allergic reactions to a drug are not hard to identify, and many doctors are skilled at spotting dramatic changes in your breathing or blood pressure. It's important to tell the doctor you see what medications you have taken and how long ago you took them.
Know the signs of severe cutaneous adverse reactions (SCARs)
In the more delayed type of rash, symptoms can be more difficult to diagnose. The most common triggers for these types of rashes include antibiotics, antiseizure medications, antigout medications like allopurinol, and even over-the-counter medications like NSAIDs. (This isn't a complete list, and any new medication should be regarded with caution.)
As for the rash, when it's just itching things are usually fine, but still a nuisance. When the skin starts to hurt, or turns a deeper purple color, doctors worry about something more serious. If your skin starts to blister up or you see pustules, or if you notice sores in your mouth, eyes, or your genitalia, these are red flags and you should get to an urgent care clinic or the ER and ask for a dermatology consultation. Sores in the mouth can be so severe that drooling becomes a common symptom, because patients avoid swallowing due to the pain.
If you start to feel ill, like you have the flu, or if you're getting puffy from swelling, especially in the face, this could mean it's a severe drug hypersensitivity syndrome. Sometimes people develop a fever, a drop in their blood pressure, or their liver, kidneys, and heart can all be affected by drug hypersensitivity syndromes. These are so severe that most patients need to be admitted to the hospital, and sometimes even to the burn or intensive care unit.
While there are different names for different types of severe drug reactions, including Stevens-Johnson syndrome (SJS), drug rash with eosinophilia and systemic symptoms (DRESS), and acute generalized exanthematous pustulosis (AGEP), they are often grouped together as severe cutaneous adverse reactions (SCARs).
What happens if you develop a SCAR from a medication?
The first step is getting evaluated by a specialist, either in a dermatological clinic or the hospital. Finding someone who has expertise in managing these types of reactions is critical. A doctor (usually a dermatologist) may biopsy your skin, and they may have to start systemic medications that suppress your immune system. Sometimes, patients with SCARs also require a stay in a hospital.
The most important thing you can do is to keep an eye on your skin and its symptoms if you're taking a new medication, or even if you've increased the dose of an old medication. If you suspect that you may be dealing with one of these SCARs, be sure to seek help from an expert, like a board-certified dermatologist, so that you can rest assured that you're getting the care you need. Patients who are treated appropriately generally do well. Your doctors should also report these reactions to the FDA.
Once you're on the mend, things can start to get back to normal, but it's important to follow up with your doctors because there are some long-term issues that are important to pay attention to. Ultimately your doctors and healthcare team will advise you on what exactly is safe in the future. Remember that if you're worried about one of these reactions, it's important to stop the medication as soon as possible, but with the input of your doctors.
